This invention relates to a revolving block for a high place working vehicle having a working implement such as a revolving ladder or boom mounted thereon, and more particularly it relates to a revolving table having an inclination correcting mechanism housed therein.
In this type of high place working vehicles, it is necessary to secure safety of operation by ensuring that the revolving type working implement operates always in a vertical place. Therefore, if the vehicle is placed on the inclined ground, the inclination of the working implement must be corrected somehow. As for the method of correcting the inclination of the boom on the revolving table, it is known to provide a separate correcting device adapted to ensure that the boom operates in a vertical plane, or to utilize the outrigger to make the entire vehicle horizontal. In the case of the former known method, however, the vehicle remains inclined and hence the revolving table remains inclined while the inclination of the boom alone is corrected, so that each time the position of revolution changes, a correcting operation is required, which is irrational. Further, the addition of the separate correcting device complicates the whole structure and involves an increase in cost. With the latter known conventional method, when the vehicle is made horizontal by the outrigger, the front or rear wheels are separated from the ground, so that it is required that the outrigger be rugged and have a sufficient stroke to raise the vehicle. Further, from the standpoint of safety of operation when the wheels are lifted in the air, the attaching position of the outrigger is limited and hence the design of the high place working vehicle is complicated.